Massive outreach efforts by the Obama and Romney campaigns — essential in a neck-and-neck contest like this one — are shaking things up in critical swing states, according to the latest release from the Washington Post-ABC News tracking poll.

Over the past month, the dueling presidential operations have each contacted about 20 percent of all likely voters nationally. In the eight most heavily targeted states — the seven Washington Post “toss-up” states plus Ohio — voter contacts are sharply higher, with the Romney campaign appearing to close the gap in this important area as the election nears.

Overall, the national contest has tipped back to 49 percent for Republican Mitt Romney and 48 percent for President Obama. This is not a significant shift from yesterday’s 50 to 47 percent edge for Romney, and a return to the numbers from the previous two days.

Nearly four in 10 voters, 37 percent, in the eight swing states — Colorado, Florida, Iowa, Nevada, New Hampshire, Ohio, Virginia and Wisconsin — say they have personally been asked for their support by a representative of the Obama campaign, either by phone, in-person or online in the past month. About as many, 35 percent, say they have heard from Romney’s side. Two weeks ago, more voters in this collection of states said they had recently heard from Obama than Romney.

Looking just at reported contacts in the past week, the campaigns are equally matched: 28 percent of all likely voters in swing states say they’ve heard from the Romney campaign, and 27 percent say so of Obama’s.

Of course, what really matters is whether or not the campaign contacts are having any effect. According to Jon Cohen, who wrote the piece for The Fix, it’s a clear cut conclusion can’t be drawn.

Whether the campaign contacts are persuasive or they are simply good at targeting voters likely to affiliate with their candidate is unclear, but the possible effects on turnout are hugely important.

In the swing states, voters who report any contact from the Obama campaign break for the president 68 to 30 percent; those who have not heard from his side shift to 63 to 34 percent against him.

The numbers run in the opposite direction looking at Romney contacts. The Republican is up 59 to 40 percent in these eight states among likely voters contacted by his campaign. It’s a basically even divide among voters not contacted by a GOP representative.

At this point in the game, I’m going to go with Cohen’s latter assessment, that the campaigns are good at targeting voters likely to affiliate with their candidate.

The undecided vote is small, so the likely way of reaching them is through TV, radio and news. Certainly there will be persuasion calls and direct mail pieces, but those precious resources are likely better spent at this time in the campaign on turning out the base.

In my opinion, this race is going to be won according to turnout, and that’s likely the focus of voter contact operations right now. Obama needs to get those first-time voters who supported him in 2008 back to the polls, and Romney needs a large evangelical turnout in places like Ohio. Without that, neither can win, regardless of how undecided voters break.